1. Field of the Invention
The present invention relates to an ink cartridge. In particular, the present invention relates to a color ink cartridge preferably using three colors, such as cyan, magenta and yellow, and having discrete ink feeding passages for the ink of respective colors.
2. Description of the Related Art
In general, an ink-jet printer prints out a desired image by spraying ink onto printing paper. The ink-jet printer is provided with an ink cartridge as a consumable article for storing a predetermined quantity of ink. Representative prior art examples of ink-jet printers have been disclosed in U.S. Pat. Nos. 5,926,195, 6,260,961 and 6,293,664, the entire contents of which are incorporated herein by reference.
FIG. 1 is a perspective view showing a part of a prior art ink cartridge is disclosed in U.S. Pat. No. 6,260,961. As shown, the ink cartridge comprises a body 70 and a plurality of ink compartments 84, 86, 88 defined in the body 70 by a plurality of partitioning walls 80, 82. The ink chambers 84, 86, 88 form individual flow channels via a plug 66 fitted into a slide insert opening 76a. A Tape Automated Bonding (TAB) circuit 204 with a plurality of cavities 202 is mounted onto the plug 66. With the ink cartridge constructed as described above, ink feeding channels for feeding ink from the individual ink chambers 84, 86, 88 into the cavities 202 provided in the TAB circuit 204 are integrally formed in the body 70. The ink feeding channels are individually formed in the ink chambers 84, 86, 88, respectively.
However, the ink cartridge as described above has a limited ink feeding capability because it is difficult to form cavities for feeding ink to the TAB circuit 204. The area of the ink feeding ports is reduced when a wall body is formed for attaching a filter (not shown) due to a narrow physical space for such an arrangement. As such, inks cannot be smoothly fed from the individual ink chambers 84, 86, 88 to the cavities 202 at the time of high-speed printing. Consequently, droplets of ink fed to a print head (not shown) via the cavities 202 become irregular, thereby deteriorating the quality of image.
In addition, in order to form the ink feeding channels, it is necessary to seal the opening 76a formed in the front face of the ink cartridge via the plug 66, the plug 66 may be installed on the rear surface of the TAB circuit 204. Therefore, upon failing to precisely adjust the height of the plug 66 when attaching the plug 66, the plug 66 protrudes causing interference between the TAB circuit 204 and plug 66. In such a case, the electrical connection to the ink cartridge 50 may be out of order, thereby disturbing the normal printing operation and reducing the reliability of the product.
Furthermore, because the plug 66 is required to seal at least two ink feeding channels, it is necessary to provide partitioning walls to define the individual ink feeding channels on the plug 66. As a result, there is problem in that the shape of the plug 66 becomes complicated, whereby manufacturing costs can be increased and leakage of inks and mixture of colors can be produced in the sealed portion.
If the ink feeding channels are formed on the lateral opposite sides of the print head as described above, the ink feeding channels are completed by the plug 66 being attached to the front face of the ink cartridge. The ink feeding channels completed in this manner have a large volume as compared to ink cartridges of other types. Such a large volume may counterbalance negative pressure caused by capillary attraction produced by a foam member for containing ink, thereby deteriorating the characteristic of negative pressure. In order to overcome this problem, it may be possible to add a certain shape to the plug 66 so as to reduce the volume of the ink feeding chamber. However, this may result in additional processes when fabricating a mold and increase the material costs.